This invention relates to plug and receptacle electrical connectors, and more particularly, to a combination plug and combination receptacle for coupling computer terminals at a remote location to a cluster terminal control unit.
Access to computers may be had in many locations in the same building, (i.e., LOCAL) or beyond the local capability (REMOTE) such as those separated in different cities requiring interconnecting communication systems such as leased lines, communication satellites, etc. ALL LOCAL or REMOTE stations or satellites have a common denominator which is that they contain computer terminal devices such as video display terminals, printers and other equipment which must be connected to an electrical power source as well as a communication line normally in the form of a coaxial cable which links the terminal device to the cluster terminal control unit, whereupon and varying by local or remote, it is connected to the central processor. The coaxial cable is connected from the terminal to a control unit, for example, an IBM 3274 cluster terminal controller. Ordinarily, the computer terminal devices are permanently connected; that is, plugged into an electrical power outlet in a pre-wired situation, e.g. as a wall outlet, and located such that the power cord is not susceptible to being tripped over. In addition to the power connection, the terminal needs a coaxial cable connection, usually one continuous cable, to the cluster terminal control unit. The cable connection at the terminal end called a BNC Bulk Head Receptacle has a single wire located centrally at the end of the coaxial cable. Disconnecting and reconnecting the coaxial cable at the terminal end is not trouble-free as the wire can easily bend or break. Furthermore, the point at which the coaxial connector connects to a computer terminal device (BNC Bulk Head Receptacle) is usually located in a difficult to reach area such as at the back or near to the bottom of the device and is often embedded in a special concealed compartment.
Using the traditional method of permanently dedicating a terminal at the user's work area for each light to medium activity user requires more terminals than the work load requires. Using the alternative traditional method, that is a common terminal area which is established within a reasonable distance of a group of light to medium activity users is more efficient in the sense that it requires fewer terminals to support the group of targeted users; however, since the common terminal area is away from the individual's work area using the common area is very inconveninent since one loses immediate access to the individuals' work area which may be required in conjunction with the terminal. This is the main reason why, although infrequently used, terminals may be dedicated at each users' area.
Under any circumstances however, either permanently dedicating a terminal for each user or establishing a common area for terminal processing which is pre-wired, may unnecessarily tie-up and require multiple computer terminal equipment which is not fully utilized, or may be inconvenient to the user who doesn't have a permanently attached terminal at his location and must move to a common terminal area, or otherwise gain access to a computer terminal at some other location. Accordingly, in situations where light to medium computer terminal activity is required, it is inefficient to dedicate terminals to each user or to inconveniently establish a common area for terminal processing.
The present invention is directed to the solution of this problem in which the terminals may be moved from one location to another as needed and merely plugged in so that when a user requires the use of computer terminal equipment, the terminal is merely moved to the user's location and plugged in.